I think those who have replied in defense of Apple here are missing the point. Iphone is a best-in-class device. It was until now bundled with a best-in-class mapping and location visualisation application, with best-in-class data behind it. The combination was best-in-class, and millions of people's lives have adapted to use and even depend upon it.
Unless Apple were under some pressure we don't know about, deciding to replace that app with something that fronts a vastly inferior data set containing many factual errors, rendering it manisfetly less fit for purpose than its predecessor is indeed extraordinary.
Nobody in their right mind can believe this is in the short term interests of the user base, and frankly I think it will be at least a matter of years before the usability gap between the new IOS6 maps app and its predecessor closes sufficiently.
I'm trying hard to believe Apple have worked out that the ultimate benefit of this slap in the face to its users is worth the risk. But I can't really. Just a crazy decision I fear.